Pocket Medicine: The Massachusetts General Hospital Handbook of Internal Medicine (87 page)

Treatment

• Rx if can initiate
w/in 72 h of skin lesions
in healthy Pt or at
any time
in immunosupp.

• Valacyclovir or famciclovir × 7–14 d, or until lesions fully crusted; acyclovir 10 mg/kg IV q8h if dissem. or high-risk Pt (medically ill, immunosupp., V1 zoster w/ ophthalmic s/s, etc.) • Prevention: vaccine approved for Pts >50 y (↓ lifetime risk from 20% to 10%, also ↓ PHN)

BACTERIAL ENDOCARDITIS

Definition

• Infection of endothelium of heart (including but not limited to the valves) • Acute (ABE): infxn of normal valves w/ virulent organism (eg,
S. aureus
, group A or other β-hemolytic strep,
Strep pneumo
) • Subacute (SBE): indolent infxn w/ less virulent organism (eg,
S. viridans
); often abnl valves
Predisposing conditions

•
Abnormal valve

High risk:
prior endocarditis, rheumatic valvular disease, AoV disease (incl. bicuspid), complex cyanotic lesions, prosthesis (annual risk 0.3–1%)

Medium risk:
MV disease (including MVP w/ MR or leaflet thickening), HCMP

•
Abnormal risk of bacteremia
: IDU, indwelling venous catheters, poor dentition, hemodialysis, DM, intracardiac devices (eg, pacemaker, ICD)

Clinical manifestations
(
Archives
2009;169:463)

•
Persistent bacteremia
:
fever
(80–90%), chills, night sweats, anorexia, wt loss, fatigue •
Valvular or perivalvular infection
: CHF, conduction abnormalities •
Septic emboli
: systemic emboli (eg, to periphery, CNS, kidneys, spleen or joints), stroke,

PE (if right-sided), mycotic aneurysm, MI (coronary artery embolism)

•
Immune complex phenomena
: arthritis, glomerulonephritis,
RF, ↑ ESR

•
SBE:
can p/w fatigue, nonspecific sx in Pts w/o risk factors; ∴ need high index of suspicion
Physical exam

• HEENT:
Roth spots
(retinal hemorrhage + pale center),
petechiae
(conjunctivae, palate) • Cardiac:
murmur
(85%),
new
valve regurgitation
(40–85%) ± thrill (fenestrated valve or ruptured chordae), muffled sounds (PV).
Frequent exams
for Δ murmurs, s/s CHF.

• Abdomen: tender splenomegaly; musculoskeletal: arthritis, vertebral tenderness • Extremities (
typically seen in SBE, not ABE
)

Janeway lesions
(septic emboli → nontender, hemorrhagic macules on palms or soles)

Osler’s nodes
(immune complexes → tender nodules on pads of digits)

proximal
nail bed splinter hemorrhages (8–15%); petechiae (33%); clubbing

• Neuro: Δ MS or focal deficits • Devices: erythema, tenderness or drainage at catheter site, PM/ICD pocket tenderness
Diagnostic studies

•
Blood cultures
(
before abx
): at least 3 sets (aerobic & anaerobic bottles) from different sites, ideally spaced ≥1 h apart. ✓ BCx (at least 2 sets) after appropriate abx have been initiated to document clearance; repeat q24–48h until
.

• CBC w/ diff (↑ WBC common in ABE; anemia in 90% SBE), ESR, RF, BUN/Cr, U/A, & UCx •
ECG
(on admission and at regular intervals) to assess for new conduction abnormalities •
Echocardiogram
: obtain TTE if low clinical suspicion, expect good image quality; TEE if (i) mod-to-high suspicion, (ii) high-risk Pt (prosthetic valve, prior IE, congenital heart dis), (iii) TTE nondx, (iv) TTE
but high-risk endocarditis, or (v) suspect progressive or invasive infection (eg, persistent bacteremia or fever, new conduction abnl, etc.) (
Circ
2005;111:e394)

•
Cx
endocarditis
: may be due to abx prior to BCx. PCR, bacterial 16S ribosomal RNA, serologies may be helpful. Detailed hx: animal exposure, travel, unpasteurized dairy,
etc.
Seek ID eval (
Med
2005;84:162;
NEJM
2007;356:715).

Treatment
(
NEJM
2013;368:1425)

•
Obtain culture data first

ABE → abx should start promptly after cx data obtained

SBE → if Pt hemodynamically stable, may delay abx to properly obtain adequate BCx data, esp. if prior abx used

•
Suggested empiric therapy
(
Circ
2005;111:e394)

native valve ABE
:
vanco
(± gent; no longer routinely recommended)

native valve SBE
:
ceftriaxone
(
or
amp if ? enterococcus; eg, older
or ob/gyn) ±
gent

PVE
:
early
(≤60 d):
vanco + cefepime + gent
;
intermediate
(60–365 d):
vanco
+
gent
;
late
(>1 y):
vanco + CTX + gent

native or prosthetic cx
:
depends on host & epi
,
seek ID consultation